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305 -> 454 Swap

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by HeatMizer, Sep 27, 2000.

  1. HeatMizer

    HeatMizer Newbie

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    Hey, I'm putting in a 454 into my 87 blazer. Any tips? What will I have to change? I want to keep the computer. I understand that there is no provision for Torque convertor lockup? No knock sensor either. What about motor mounts? The 454 came from an 89 suburban, but I got a performer TBI manifold and mild cam set. Any other performance tips? 310-70R15 tires. Should I change the rear to posi? Please help. All advice appreciated!
     
  2. Roostr84

    Roostr84 1/2 ton status

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    If the 454 came out of an 89 and was original I would think it would have a knock sensor. Also I am not sure about the wiring to the tbi but you will definetly have to burn a custom chip to accomodate your current trans and it should lock up if you do it right.
     
  3. BigJim85

    BigJim85 1/2 ton status

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    You'll need a larger radiator. Pick one up for an 89 Suberban with a 454, it'll bolt right in place of the old one.
     
  4. dumbfounded

    dumbfounded 1/2 ton status

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    Injectors, computer, and maybe a fuelpump will have to be changed. The 454 obviously drinks a hell of alot more gas than the 305. The throttle body will more than likely have to be changed b/c it won't flow enough cfm's..

    Love, Peace, and Hair Grease...........
     
  5. HeatMizer

    HeatMizer Newbie

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    Thanks guys. So far I've got the motor bolted in. I've found you can use the small block motor mounts, but they should be mounted to the block prior to dropping it in. I've also learned that I can get a custom chip from Hypertech which will keep the TCC lockup functional despite having 454 parameters. Also, I ordered a flexplate from Jegs since the orignal 454 flex plate wouldn't bolt up to the 700R4 torque converter (which I was told will be suficient as long as I don't have to radical of a cam.) I have been to several junkyards looking for radiators, fan shrouds etc. but they all tell me the same story... big block stuff goes fast. I'll keep you posted as I go and will eventually post a picture of it. Any additional tips are still appreciated!
     

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